A negative-leaning summary of Fanapt's clinical data in schizophrenia is included for the first time in the seventh edition of the Manual of Clinical Psychopharmacology, published this week by the American Psychiatric Association.

The authors of the manual raise concerns about Fanapt's dosing, side effects and high cost compared to other drugs used to treat patients with schizophrenia.

"It is unclear to us exactly where iloperidone is going to fit in the treatment of schizophrenia," the manual's authors conclude, using the scientific name for Fanapt.

A conclusion like that in an influential psychiatric reference book is not likely to help Novartis ( NVS) as it tries to sell Fanapt to doctors who have ample choices in the hyper-competitive schizophrenia drug market.

Novartis did not respond to a request for comment on the Fanapt summary in the Manual of Clinical Psychopharmacology.

Novartis announced first-quarter Fanapt revenue of $21 million, but wholesaler inventory stocking accounted for most of that amount. Novartis did not break out Fanapt's end-user sales from inventory stocking in its first-quarter financial report. David Moskowitz, drug analyst at Madison Williams, estimates that Novartis only sold about $1 million of Fanapt to schizophrenia patients in the first quarter based on his analysis of the IMS data.

Like Vanda, Titan Pharmaceuticals ( TTNP.PK) also receives royalties based on Fanapt sales so it is similarly affected by the outcome of drug's commercial push.

The Manual of Clinical Psychopharmacology, first published in 1986, is the standard drug reference guide used by psychiatrists. The manual is written by three noted psychopharmacologists to provide clinical reviews and practical advice for the use of drugs in the treatment of psychiatric disease.

The manual's discussion of Fanapt, which belongs to the class of drugs known as second-generation antipsychotics (SGA), is not all kind.

The FDA approved Fanapt in 2009 "unexpectedly" after first rejecting the drug in 2007 due to efficacy and safety concerns, the authors state. The Fanapt entry notes two, phase III studies established Fanapt's efficacy, but then follows with a lengthy discussion of the drug's side effects and dosing issues.